中温结合乙醇处理对枯草芽孢杆菌芽孢皮层裂解酶活性及结构的影响  

Effect of medium temperature and ethanol on Bacillus subtilis cortex-lytic enzyme activity and structure

作　　者：陈翔 曾朝玮 申瑾 郭家俊 章中[1] CHEN Xiang;ZENG Chaowei;SHEN Jin;GUO Jiajun;ZHANG Zhong(College of Agriculture,Ningxia University,Yinchuan 750021,China;Quality Standards and Testing Institute of Agricultural Technology,Yinchuan 750002,China)

机构地区：[1]宁夏大学农学院,宁夏银川750021 [2]宁夏农产品质量标准与检测技术研究所,宁夏银川750002

出　　处：《食品与发酵工业》2019年第23期37-42,共6页Food and Fermentation Industries

基　　金：国家自然科学基金项目(31760474);国家自然科学基金项目(31460410)

摘　　要：以枯草芽孢杆菌芽孢皮层裂解酶为研究对象,研究中温结合乙醇处理对其活性及结构的影响。采用紫外可见分光光度法测定酶活性,荧光光谱和傅立叶变换红外光谱法(fourier transform infrared spectroscopy,FTIR)分析处理前后酶二三级结构的变化。结果表明,80℃结合体积分数为30%、75%乙醇处理20 min时,杀灭芽孢效果最佳,皮层裂解酶活性最弱,仅为(24.3±2.73)、(20.42±2.17)U/L。中温结合乙醇处理使皮层裂解酶荧光强度下降,80℃时红移3 nm,三级结构发生变化。随着温度和乙醇体积分数逐渐增加,二级结构发生变化,α-螺旋及β-折叠含量减少、无规卷曲含量显著增加,75%(体积分数)乙醇80℃处理时变化最显著,含量分别为(10.98±0.03)%、(25.41±0.03)%、(48.24±0.06)%、(15.37±0.02)%。中温结合乙醇处理后皮层裂解酶结构发生变化,从而导致酶活力的改变。The effect of temperature and ethanol treatment on Bacillus subtilis spore cortex-lytic enzyme activity and structure was studied.The activity of the enzyme was determined using UV-visible spectrophotometry,and the changes of secondary and tertiary structures of the enzyme before and after treatment were analyzed using fluorescence spectroscopy and Fourier transform infrared spectroscopy(FTIR).The results showed that when the culture was treated with 30 and 75%ethanol at 80℃for 20 min,the effect of spores denaturation was the best,and the activity of cortical lyase enzyme was the lowest(24.3±2.73,20.42±2.17 U/L,respectively).The temperature combining with ethanol treatment reduced the fluorescence intensity of cortical lyase enzyme,and the red shifted 3 nm at 80℃.Also,the tertiary structure changed.With the increase of temperature and ethanol concentration,the secondary structure also changed:the amount ofα-helix andβ-sheet were reduced,and random coils increased significantly.The change of secondary structure was the most significant at 80℃with 75%ethanol,the content was 10.98%±0.03,25.41%±0.03,48.24%±0.06 and 15.37%±0.02 respectively.The structures of cortex-lytic enzyme after medium temperature combining with ethanol treatment was changed,resulting in the changes of its activity.

关 键 词：枯草芽孢杆菌 皮层裂解酶 中温结合乙醇处理 灭活芽孢 

分 类 号：R28[医药卫生—中药学]